Method and apparatus for drawing in warp threads

ABSTRACT

Mechanism for drawing short lengths of thread of yarn through the weaving elements of a loom in a preselected manner while leaving an end portion of each thread exposed for subsequent tying to the thread of yarn on a warp beam.

United States Patent [191 Crandall et al.

METHOD AND APPARATUS FOR DRAWING IN WARP THREADS Inventors: Charles B. Crandall; Frederick L.

Wieneke, both of Rockford, Ill.

Assignee: Barber-Colman Company,

Rockford, Ill.

Filed: June 12, 1972 App]. No.: 262,105

[52] US. Cl. [51] Int. Cl. [58] Field of Search 28/44, 45

References Cited UNITED STATES PATENTS Fleischer 28/45 Jan. 29, 1974 3,444,601 5/1969 Wieneke, 28/45 Primary Examiner-Louis K. Rimrodt Attorney, Agent, or FirmWolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[57] ABSTRACT Mechanism for drawing short lengths of thread of yarn through the weaving elements of a loom in a preselected manner while leaving an end portion of each thread exposed for subsequent tying to the thread of yarn on a warp beam.

6 Claims, 8 Drawing Figures BACKGROUND OF THE INVENTION This invention relates to a mechanism for drawing warp threads of yarn through the weaving elements of a loom, namely, the drop wires, the heddles and the reed, in a preselected manner so that, when the weaving elements are associated with the loom and operated in a preset manner, the loom weaves the desired pattern. It has been the usual practice to draw the threads directly from a warp beam and through the weaving elements and then to transport the weaving elements and the warp beam together to the loom. This practice presents a number of problems one of the more important of which is transportation. Thus, with large warp beams, it is difficult and cumbersome to transport the weaving elements and the beam together through narrow aisles, doors and the like and it is virtually impractical to transport such an assembly from one plant to another. Moreover, this method of drawing in requires practically the full-time attention of an operator.

SUMMARY OF THE INVENTION The general object of the invention is to provide a new and improved method of drawing in warp threads which method permits the drawing in to be performed and, thereafter, the weaving elements may be transported to the loom separately from the warp beam and, also, which is essentially automatic and requires little operator attention.

The principal object is to achieve the foregoing by drawing a short length of thread through each set of weaving elements while leaving an exposed end portion so that these end portions may be tied at the loom to corresponding threads ona warp beam and the short lengths act as pilot threads for drawing the threads on the beam through the weaving elements.

Another object is to draw the short lengths of thread through a leasing apparatus associated with the weaving elements so that the tying of the short threads to the warp threads may also be accomplished automatically.

The invention also resides in the novel apparatus and mechanisms for performing the steps of the new method.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary side view of a warp drawingin machine embodying the present invention.

FIG. 2 is a fragmentary side view as seen from the right in FIG. 1.

FIG. 3 is an enlarged fragmentary sectional view taken along the line 3--3 in FIG. 2.

FIG. 4 is an enlarged fragmentary sectional view taken along the line 4-4 in FIG. 2.

FIG. 5 is a view similar to FIG. 3 but showing the parts in a moved position.

FIG. 6 is an enlarged fragmentary perspective view of the principal mechanisms used in the drawing-in operation.

FIG. 7 is a fragmentary top view of the machine.

FIG. 8 is an enlarged fragmentary perspective view of one of the mechanisms used in the drawing-in operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawings for purposes of illustration, the invention is embodied in a warp drawing-in machine in which threads 10 of yarn are drawn through the weaving elements of a loom (not shown) by a reciprocating needle 11(FIG. 6). As is customary in the art,

the weaving elements include a plurality of drop wires 12, heddles 13 in a frame 14, and a reed 15. The threads may also be drawn through lease strings l6 and 17(FIG. 6). The weaving elements, together with the lease strings, constitute a unit which is held in the warp drawing-in machine while the warp threads are drawn in and, thereafter, this unit is transported to and mounted on a loom.

More specifically, the weaving elements are mounted on a truck 18 which, as is well known in the art, is movable on tracks (not shown) to be moved toward the frame 19 and is locked in a fixed position relative to the frame of the machine during the drawing-in operation. Thereafter, the truck is separated from the machine and the weaving elements are transferred to a transport truck (not shown)to carry the elements to a loom. Adjacent each end of the truck 18 is an arm 20 which carries a horizontal bar 21 extending generally from the front of the machine toward the back and the heddle frames 14 are suspened from these bars and locked in position in the customary manner. On the front porjacent ends of the strings are tied together for transporting.

A carriage 24 is mounted on the frame19 to move from one end of the latter to the other and carry the reciprocating needle 11 along the weaving elements whereby the needle draws successive threads of yarn through these elements. At the rear of the carriage at each end of the latter are wheels 25 (FIGS. 1 and 7) which ride on a track 26 on the frame 15 and spaced rollers 27 journaled on the carriage to turn about vertical axes engage the side of the track so that the carriage moves in a straight line. A second set of wheels 28 are journaled on the front of the carriage and ride on a second track 29 on the frame. The carriage 24 is advanced along the frame by a feed motor 30(FIG. 7) which, through a speed reducer 31, drives a pinion 32 engaging a rack 33 on the track 26. The motor is energized and deenergized to step the carriage along the frame under the control of a mechanism 34 which is responsive to the opening of successive dents in the reed 15, this control being disclosed in Wieneke US. Pat. No. 2,807,861, issued Oct. 1, 1957.

The needle 11 is an elongated flexible metal strip with a book 35 (FIG. 6) formed on its projecting or outer end. In its withdrawn position, the needle is disposed within semi-circular housing 36 (FIGS. 1 and 7) with the needle against the arcuate track 37 of the housing and the hook 35 behind the reed 15. The inner end of the needle is attached to the outer end of a horizontal arm 38 which turns about an axis a which is the center of the arcuate track 37. When the arm 38 is turned counterclockwise as viewed in FIG. 7, the needle is projected through a dent in the reed 15, a selected heddle 13, one of the drop wires 12 and between the lease strings l6 and 17. In the projected position of the needle, the latter is supported by a channel-shaped guide 39 (FIG. 6) and the hook engages a thread of yarn which, as will be described more in detail later, is positioned for engagement by the needle by a spiral cam 40 rotatably mounted on the carriage. As the arm 38 is turned in the opposite direction, the thread is drawn over a horizontal guide 41 on the truck 18, through the lease strings and weaving elements. The arm is turned back and forth by a main drive motor 42 (FIG. 7) mounted on the carriage 24 through a shaft 43 and mechanism (not shown) well known in the art.

Journaled in a horizontal row on arms 44 (FIG. 1) of the carriage 24 are worms 45, there being one worm for each heddle frame 14. Before the needle 11 is projected each time, a selected one of the worms is turned depending upon the pattern to be woven by the loom to twist the next free heddle in the associated frame through 90 degrees to present the hole 46 in the heddle (FIG. 6) to the needle. Similarly, worms 47 are carried by the carriage with one associated with each rank of drop wires12, there being four ranks in the illustrated embodiment. Again, before the needle is projected, one of the worms 47 twists an associated drop wire to present the hole 48 (FIG. 6) in the latter to the needle, it being customary to present drop wires from successive ranks in repeating order upon successive projections of the needle. As is well known in the art, the main drive motor 42 turns selected ones of the worms and 47 for each reciprocation of the needle through a pattern control mechanism 50 (FIG. 7).

At the beginning of the drawing-in, one of the lease strings l6 and I7 is above the other so that the needle 11 passes between the strings and draws the thread of yarn under one string and over the other. With the parts in the position shown in FIG. 6, the needle will draw the next thread of yarn under the string 16 and over the string 17. Before the next thread is drawn in, the string 16 islowered and the string 17 is raised so that this thread passes under the string 17 and over the string 16. The positions of the strings are reversed between each reciprocation of the needle and thus the lease strings keep the warp threads separated and in proper sequential order.

To move the lease strings 16 and 17 up and down, the latter are threaded through holes in the upper ends of upright arms 51 and 52 (FIG. 6) respectively and the arms reciprocate vertically between rollers 53 journaled on an arm 54 of a block 55 which is mounted on the carriage 24. Followers 56 and 57 carried on the lower ends of the arms ride respectively on cams 58 and 59 fast on a shaft 60 which, through suitable mechanism (not shown) is turned by the main drive motor 42, the followers being held down against the cams by contractile springs 61 acting between the carriage and the arms 51 and 52. The rises 62 and 63 on the earns 58 and 59 are angularly spaced apart 180 to raise one lease string while the other is lowered.

With the foregoing arrangement, the carriage 24 initially is positioned at the left end of the frame 19 as viewed in FIG. 7 with the needle 11 in its retracted position within the housing 36. The first dent in the reed I5 is opened, the motor 42 through the pattern control mechanism 50 turns a selected one of the worms 45 and a selected one of the worms 47 to twist the proper heddle and drop wire, the cams 58 and 59 space the lease strings l6 and 17 vertically, and the spiral cam 40 positions a thread of yarn for engagement by the needle. The motor 42 then turns the arm 38 to project the needle through the opened reed dent and the twisted heddle and drop wire, between the lease strings and into engagement with the thread with the latter in the hook 35. The arm 38 then is swung in the opposite direction to retract the needle and draw the thread between the lease strings and through the selected drop wire and heddle and the open reed dent. A stripper 64 (FIG. 1) then swings in a manner well known in the art to remove the end of the thread from the needle hook 35. Next, the feed motor 30 steps the carriage 24 to the right to aline the hook of the needle with the next reed dent which is opened while the positions of the lease strings are reversed and a second heddle and the next drop wireare positioned and twisted. The needle then is projected and retracted to draw in a second thread and the cycle is repeated until all the threads have been drawn in. It should be understood that the functions described occur at high speed and movement of the carriage across the frame is virtually continuous.

It has been the practice to mount not only the weaving elements on the truck 18 but also the warp beam (not shown) and, after the drawing-in is completed, to transfer the beam as well as the weaving elements to the transport truck, and transport all to the loom. With large warp beams, this presents problems such as transporting the elements and the warp beam along narrow aisles and through doors and it is impractical to transport the assembly from one plant to another. To overcome these disadvantages, the present invention contemplates a novel method and apparatus by which short pilot threads are drawn through the weaving elements which then, with these threads, are transported to the loom independently of the warp beam. At the loom, each thread of yarn on the warp beam is tied to the end of the corresponding pilot thread and the pilot threads are then used to pull the threads on the warp beam through the weaving elements. If the pilot threads are leased as described above, this tying may be performed automatically by a warp tying machine even in cases such as when a color pattern is to be woven.

Because color has no significance as regards the pilot threads, the latter may be cut from a single package 65 (FIG. 1) of undyed yarn, the package conveniently being mounted on a horizontal arm 66 on a vertical support plate 67 suitably secured to the carriage 24 to move with the latter. According to the novel method, yarn is pulled off the package 65 and up through the spiral cam 40 where it is engaged by the needle 11 and drawn between the lease strings 16 and 17 and the weaving elements 12, 13 and 15. The thread of yarn is out leaving a short free end 68 which is held temporarily in a conventional card bar 69 (FIG. 1) on the frame 19. As the thread is cut, the new end of the yarn on the package is gripped and the process is repeated.

To carry out this method, two shear-clamp assemblies 70 and 71 are carried by an endless chain 72 which is disposed in front of the machine and in a plane parallel to the path of movement of the carriage. The chain is trained over an idler sprocket wheel 73, which is journaled on the plate 67 adjacent the upper end thereof, and around a driven sprocket wheel 74 disposed near the bottom of the plate. The latter is fast on a shaft 75 (FIG. 2) which is driven by the motor 42- (FIG. 7) through shafts 76 and 77, sprockets 77', a chain 77" (FIG. 1) and a gear box 78. The shear-clamp assemblies and 71 are equally spaced along the chain 72, that is, they are spaced apart the same distance in both directions along the chain.

The shear-clamp assemblies 70 and 71 are identical in construction and, as shown in FIGS. 3 and 5, each includes stationary first fingers 79 and 80 which guide the yarn from the package 65 between second fingers 81 and 82 mounted respectively in front of the fingers 79 and 80, the finger 81 being stationary and the finger 82 being swingable toward and away from the fingers 79 and 81. As is customary in assemblies of this type, an axial tension spring 82' (FIG. 8) holds the finger 82 either in the closed position shown in FIG. 3 or in the open position illustrated in FIG. 5. As the finger 82 swings toward the finger 81, it first clamps the yarn against this finger and then cooperates with the finger 79 to shear the yarn leaving the short thread drawn through the weaving elements while the fingers 82 and 81 still grip the new free end of the yarn on the package 65. Thus, the fingers 81 and 82 constitute the clamp of the assembly and the fingers 79 and 82 coact as shears. Mounted on the plate 67 beneath the sprocket wheel 74 is a stationary cam 83 which engages and swings the finger 82 of each shear-clamp assembly toward the fingers 79 and 81 and also on the plate adjacent the sprocket wheel 73 is a stationary cam 84 which engages and swings the finger 82 back to the open position. Thus, the shear-clamp assemblies are open as each moves down the inactive run 85 (FIG. 2) of the chain 72 and are closed as they move up the active run 86.

As an assembly moves up the active run, it draws yarn from the package 65, the yarn extending from the package around a tension roller 87 on the arm 66 to the shear clamp.

To support the spiral cam 40 in the carriage 24, the cam is fast on one projecting end of a shaft 88 (FIG. 6) which is journaled in spaced bearing members 89 integral with a mounting block 90 fastened to the plate 67. The cam 40 is turned in timed relation to the operations of the other mechanisms by the motor 42 through a sprocket wheel 91 (FIG. 2) which is secured to the same shaft 75 as is the sprocket wheel 74. An endless chain 92 is trained around the sprocket wheel 91 and a sprocket wheel 93 journaled 0n the plate 67 adjacent the spiral cam (See FIG. 6). A shaft 94 keyed to the sprocket wheel 93 and journaled in an arm 95 on the block 90 carries a conical gear 96 meshing with a conical gear 97 on the other end of the shaft 88 thus completing the drive of spiral cam 40.

In order to hold each pilot thread as the upper end portion of the thread is being drawn in by the needle 11, the thread is gripped below the needle by a stationary clamp 98 (FIGS. 4 and 6). Herein, the clamp includes a horizontal fixed jaw 99 which is on one end of the block 55, the latter being fastened to the edge of the plate 67 The movable jaw 100 of the clamp 98 is carried on the end of one arm 101 of a bell crank lever 102 which is journaled in a bracket 103 to turn about a veritcal axis, the bracket being mounted on the plate 67. A rod 104 projects horizontally from the other arm 105 of the lever 102 and into a slot 106 in the lower arm 107 of a second bell crank lever 108 which is fulcrumed between its ends onportion 109 of the block 90 to swing about a horizontal axis. A follower roller 110 on the other arm 111 of the lever 108 rides on a cam 112 which is fast on a shaft 113 journaled in the block portion 109. Also fast on the shaft 113 is a spur gear 114 which meshes with a pinion 115 keyed to the shaft 88. A contractile spring 116 connected at one end to an anchor 117 on the plate 67 and at the other end to a pin 118 on the lever arm 107 biases the clamp 98 toward its open position and holds the follower 110 against the cam 112. By turning the cam through the same drive used for the other mechanisms, the clamp 98 is opened and closed in the proper timed relation to the operations of these other mechanisms.

As is customary in warp drawing-in machines, a stripper 119 (FIG. 6) operates after a thread has been drawn in to move that thread and its associated heddles 13 and drop wire 12 to the left as viewed in FIG. 6 to make room for the next thread to be drawn in. The stripper is an upright arm secured to a shaft 120 conveniently mounted on the carriage 24 with its upper end portion normally to the right of the path of the needle 11. Legs 121 project downwardly from the shaft 120 at an angle to each other and carry follower rollers 122 which straddle a cam 123 on the camshaft 60. The rotation of the camshaft is timed so that, together with the shape of the cam, the stripper arm 119 is momentarily swung to the left and then back as the needle reaches its retracted position. The stripper 1 19 operates in conjunction with the usual strippers 119 (FIG. 1).

Another stripper 124 (FIGS. 1 and 8) is operable after each pilot thread is cut from the package 65 to place the lower end of that thread in the card bar 69. In the form illustrated, this stripper is a horizontal arm with its inner end fixed to a vertical shaft l25 driven from the gear box 78 so that this stripper also functions in the proper timed relation to operations of the other mechanisms. The stripper 124 is disposed in a plane just below the card bar and normally projects forwardly as illustrated in solid lines in FIG. 8 with a hook 126 on its outer end behind the thread 10 being drawn in. As this thread is cut from the supply package, the stripper swings to the left toward and then under the card bar as shown by the broken line positions, the hook 126 carrying the thread into the card bar. Preferably, a horizontal felt pad 127 is disposed slightly beneath the stripper so that the latter retains control of the thread as it swings. The pad may be mounted on the plate 67 by means of a bracket 128. When the stripper has placed the thread in the card bar, it continues to swing in the same direction until it is back to its starting position, it being understood that the stripper turns contin uously during the drawing-in.

Although the operation is described below as a sequence of steps, it will be apparent that some steps occur concurrently and some overlap. A cycle begins with one of the shear-clamp assemblies such as the assembly 70 being closed by the cam 83 when the assembly is in the broken line position shown in FIG. 2. As a result, this assembly grips the end of the yarn on the package 65 and draws the yarn up along the active run 86 of the chain 72. The yarn passes between the jaws 99 and 100 of the stationary clamp 98 and through the spiral cam 40. During this time, the first dent of the reed 15 has been opened, the selected heddle 13 and drop wire 12 have been positioned and twisted and the needle 11 is advancing through these elements and between the lease strings 16 and 17. By the time the needle is fully projected, the spiral cam 40 has turned sufficiently to lay the yarn over the needle as illustrated in FIG. 6 so that the yarn will be engaged by the hook 35. As the needle begins to retract, the shear-clamp assembly 70 approaches the cam 84 which opens the finger 82 of this assembly thereby releasing the yarn end. At about the same time, the cam 112 closes the stationary clamp 98 which grips and holds the yarn until the free position of the yarn above the clamp 98 has been drawn over the guide 41, between the lease strings 16 and 17, through the selected drop wire 12 and heddle 13, through the reed and is stripped from the needle by the stripper 64 after which the cam 112 reopens the clamp 98. When this has been completed, the cam 123 swings the stripper arm 119 to the left to clear the yarn just drawn in and the associated drop wire and heddles for the next drawing-in.

In the meantime, the other shear-clamp assembly 71 has been traveling down the inactive run 85 of the chain 72 in the open position. Shortly after the shearclamp assembly 70 has been opened, the shear-clamp assembly 71 moves to the position originally occupied by the assembly 70 (broken line position in FIG. 2). At this point, the cam 83 swings the finger 82 of this assembly toward the fingers 79 and 81. This results in the portion of yarn which has just been drawn in being cut from the supply package '65 leaving a short thread drawn through the lease strings 16 and 17 and the weaving elements. At the same time, the assembly 71 grips the new free end of the yarn on the package 65. After being severed, the end of the short thread is swept into the card bar 69 by the stripper 124.

As the shear-clamp assembly 71 beings to carry the new free end of the yarn on the package 65 up the run 86, the cams 58 and 59 reverse the positions of the lease strings l6 and 17, a newly selected heddle 13 and the next drop wire 12 are positioned and twisted, the second dent in the reed 15 is opened, and a second short thread is drawn in in the same manner as the first. The process is repeated, using the shear-clamp assemblies 70 and 71 alternately, until the required number of short threads have been drawn in. When this has been completed, the lease strings 16 and 17 are untied from the frame 19 and the strings are tied together at both ends. Then, the truck 18 is disconnected from the frame and the weaving elements with the short threads are transferred to the transport truck and are transported to a loom where the loose ends of the short threads 10 are tied to corresponding threads of a warp beam. If the short threads have been leased, as has been described, this tying may be performed automatically by a tying machine and the warp threads will be tied in the proper order. The lease strings then are untied and removed and the short pilot threads 10 are used to pull the threads on the warp beam through 'the weaving elements.

It will be observed that, with the novel method and apparatus of the present invention, the transport truck can be comparatively small because it does not carry a warp beam or other simple transport means may be used. Thus, the transport truck is easily transported along aisles, through doors and even to distant locations. Moreover, the method may be performed with little attention of an operator.

We claim as our invention:

1. In a warp drawingdn mechanism, the combination of, a carriage having a support adapted to be disposed in front of the sets of weaving elements of a loom and movable with the carriage past the successive sets of weaving elements, a needle mounted on said carriage for reciprocating movement, means operable to move said needle through said weaving elements and into engagement with a thread and then return the needle to draw the thread through the elements, a supply of thread, gripping means on said support operable to grip the free end of the thread of said supply and draw a preselected length of thread from the supply to a position for engagement by said needle, mechanism operable to cause said gripping means to release said free end when said needle engages said preslected length of thread whereby a portion of said length is drawn through one set of weaving elements and the remainder of the length being exposed in front of that set of elements, and shearing means mounted on said support operable to cut said preselected length of thread from said supply when said needle has engaged said portion of said length, said gripping means, said needle and said shearing means repeating their functions as said carriage moves past the successive sets of weaving elements thereby to draw a preselected length of thread through each set of weaving elements while leaving a portion of each of said lengths exposed in front of the set.

2. In a warp drawing-in machine as defined in claim 1 which includes a stationary clamping means operable to grip said preselected length of thread of yarn when said gripping means releases said free end and while said needle is drawing said portion of yarn through said weaving elements.

3. In a warp drawing-in machine as defined in claim 1 which includes means for leasing said preselected lengths of yarn as the latter are drawn through said weaving elements.

4. In a warp drawing-in mechanism, the combination of, a carriage having a support adapted to be disposed in front of the sets of weaving elements of a loom and movable with the carriage past the successive sets of weaving elements, a needle mounted on said carriage for reciprocating endwise movement, means operable to move said needle through said weaving elements and into engagement with a thread and then return the needle to draw the thread through the elements, a supply of thread, an endless carrier mounted on said carriage and having an active run in front of said sets of weaving elements, means for advancing said carrier in a predetermined direction, a plurality of clamps mounted on said carrier and spaced apart a preselected distance, a plurality of shears, one for each of said clamps and each mounted on said carrier adjacent the associated clamp, a first one of said clamps being operable to grip the free end of the thread of said supply and advance the thread along said active run until the thread is gripped and cut by the following clamp and shears, said following clamp thereafter advancing the thread along said active run until gripped and cut by the next following clamp and shears thereby to present lengths of thread equal to said predetermined distance to said needle, and mechanism synchronizing the advance of said carrier, the reciprocation of said needle and the operation of said clamps and shears to cause (1 a first one of said clamps to draw a length of thread from said supply along said active run until gripped by the following clamp, (2) said needle to engage the length of thread, (3) said first one of said clamps to release the thread, (4) the needle to draw the thread through said weaving elements, (5) said shear associated with said following clamp to cut the thread leaving a portion of said length exposed in front of the weaving elements, and (6 said following clamp to draw a length of thread from said supply along said active run until gripped by the next following clamp, said carrier, said needle, said clamps and said shears repeating their functions as said carriage moves past successive sets of weaving elements thereby to draw a preselected length of thread through each set while leaving a portion of each of said lengths exposed in front of the set.

5. In a warp drawing-in machine as defined in claim 4 which includes a stationary gripper disposed along said active run in advance of said needle, and means weaving elements. 

1. In a warp drawing-in mechanism, the combination of, a carriage having a support adapted to be disposed in front of the sets of weaving elements of a loom and movable with the carriage past the successive sets of weaving elements, a needle mounted on said carriage for reciprocating movement, means operable to move said needle through said weaving elements and into engagement with a thread and then return the needle to draw the thread through the elements, a supply of thread, gripping means on said support operable to grip the free end of the thread of said supply and draw a preselected length of thread from the supply to a position for engagement by said needle, mechanism operable to cause said gripping means to release said free end when said needle engages said preslected length of thread whereby a portion of said length is drawn through one set of weaving elements and the remainder of the length being exposed in front of that set of elements, and shearing means mounted on said support operable to cut said preselected length of thread from said supply when said needle has engaged said portion of said length, said gripping means, said needle and said shearing means repeating their functions as said carriage moves past the successive sets of weaving elements thereby to draw a preselected length of thread through each set of weaving elements while leaving a portion of each of said lengths exposed in front of the set.
 2. In a warp drawing-in machine as defined in claim 1 which includes a stationary clamping means operable to grip said preselected length of thread of yarn when said gripping means releases said free end and while said needle is drawing said portion of yarn through said weaving elements.
 3. In a warp drawing-in machine as defined in claim 1 which includes means for leasing said preselected lengths of yarn as the latter are drawn through said weaving elements.
 4. In a warp drawing-in mechanism, the combination of, a carriage having a support adapted to be disposed in front of the sets of weaving elements of a loom and movable with the carriage past the successive sets of weaving elements, a needle mounted on said carriage for reciprocating endwise movement, means operable to move said needle through said weaving elements and into engagement with a thread and then return the needle to draw the thread through the elements, a supply of thread, an endless carrier mounted on said carriage and having an active run in front of said sets of weaving elements, means for advancing said carrier in a predetermined direction, a plurality of clamps mounted on said carrier and spaced apart a preselected distance, a plurality of shears, one for each of said clamps and each mounted on said carrier adjacent the associated clamp, a first one of said clamps being operable to grip the free end of the thread of said supply and advance the thread along said active run until the thread is gripped and cut by the following clamp and shears, said following clamp thereafter advancing the thread along said active run until gripped and cut by the next following clamp and shears thereby to present lengths of thread equal to said predetermined distance to said needle, and mechanism synchronizing the advance of said carrier, the reciprocation of said needle and the operation of said clamps and shears to cause (1) a first one of said clamps to draw a length of thread from said supply along said active run until gripped by The following clamp, (2) said needle to engage the length of thread, (3) said first one of said clamps to release the thread, (4) the needle to draw the thread through said weaving elements, (5) said shear associated with said following clamp to cut the thread leaving a portion of said length exposed in front of the weaving elements, and (6 ) said following clamp to draw a length of thread from said supply along said active run until gripped by the next following clamp, said carrier, said needle, said clamps and said shears repeating their functions as said carriage moves past successive sets of weaving elements thereby to draw a preselected length of thread through each set while leaving a portion of each of said lengths exposed in front of the set.
 5. In a warp drawing-in machine as defined in claim 4 which includes a stationary gripper disposed along said active run in advance of said needle, and means operable to close said gripper and grip said thread between said first clamp and said following clamp when said first clamp releases the thread thereby to hold the thread as the latter is drawn through said weaving elements, said gripper and said means repeating their functions as said carriage moves past successive sets of weaving elements.
 6. In a warp drawing-in machine as defined in claim 4 which includes means for leasing said preselected lengths of thread as the latter are drawn through said weaving elements. 